Question 205709: Hi, I need help on my summer assignment, i did all of them except two...which i don't know how to do. I'm so sorry, they have parts to them.
The first one is :
"A Glass mirror is selling mirrors with frames. The store charges 10 cents for each square inch of mirror and 25 cents for each linear inch of frame.
A. Show that a 20 inch by 30 inch mirror should cost 85 dollars
(I tried solving this by multiplying the money by the inches, and by finding the area and stuff but either it equals more or less.)
B. If there was a mirror that measures 40 inches on one side, what would the other measurement be if the price were still 85 dollars
C. Write an equation that determines the price (p) given length (l) and width (W)
D. Solve this equation for L"
If you could just do A and B that would be great because then i could figure out c and D since u will show me the work and how u did it so I know....Thank You soooo much~!
Found 2 solutions by RAY100, stanbon:
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! (A) Cost = .10*Area + .25* Perimeter
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If l=30,,& w=20,,,,Area = L*W,,,,Per = 2L + 2W
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cost = .10(30*20) +.25( 2*30+2*20)
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Cost = .10(600) + .25(100)
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Cost = 60 + 25 = $ 85
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(B) Let L=40,,,,find W
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Cost = .1A + .25P = .1(40*W) + .25( 2*40+2*W)= 4W + 20 + .5W = 4.5 W +20
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If Cost is $ 85,,85=4.5W +20,,,,65 = 4.5 W,,,,W= 14.444 in.
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(C),,,, Cost = .1Area + .25Per
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C= .1(L*W) + .25(2L+2W)
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C= .1LW + .5L +.5W
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(D) C-.5W = L (.1W +.5)
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(C-.5W) / (.1W +.5) = L,,,,,,checking with original(20*30=$85),,,ok
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! A Glass mirror is selling mirrors with frames.
The store charges 10 cents for each square inch of mirror and 25 cents for each linear inch of frame.
A. Show that a 20 inch by 30 inch mirror should cost 85 dollars
linear cost = 2(20+30)*25 cents = 2500 cents = $25.00
area cost = 20*30*10 cents = 6000 cents = $60.00
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B. If there was a mirror that measures 40 inches on one side, what would the other measurement be if the price were still 85 dollars
Let the other side length be "x"
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linear cost = 2(40+x)*25 = 2000+50x cents
area cost = 40x*10 = 400x cents
Equation:
2000 + 50x + 400x = 8500 cents
450x = 6500
x = 14.44 inches
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Cheers,
Stan H.
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